The youth of America is shifting to the left. Not politically, according to a Washington Post-ABC News poll, but physiologically.

According to the poll, the proportion of the young population that is left-handed is virtually double the proportion of older people -- 13 percent versus 6 percent.

"People aren't being forced to change anymore," said Iowa State University's Dr. Camilla Benbow, an expert in left-handedness. Prejudice against being left-handed, she said, has "given way to more rational thinking."

The poll asked people in various age groups, "Are you right-handed or left-handed?" The 1,509 people interviewed also were allowed to say "both" or "ambidextrous," although the questioner did not offer it as an option. The theoretical margin of error is plus or minus 3 percentage points.

Among people 61 and older, 88 percent said they were right-handed, 6 percent left-handed and 6 percent ambidextrous.

Among those 18 to 30, 83 percent said they were right-handed, 13 percent left-handed and 3 percent ambidextrous.

Benbow, who was not involved in the survey but was interviewed because of her research in the area, found in 1985 that children who reason well in mathematics are more likely than others to be left-handed.

She said new studies suggest that there is also a greater than expected number of left-handed chess players.

In other arenas, however, there is no difference between the righties and lefties, the poll found. There are equal proportions of both in the Democratic and Republican political parties.